3x² - xy / 9x² - 6xy + y² = x / ( ) = ( ) / 9x² - y²

问题描述:

3x² - xy / 9x² - 6xy + y² = x / ( ) = ( ) / 9x² - y²

3x² - xy / 9x² - 6xy + y²
=x(3x-y)/(3x-y)²
=x/(3x-y)
x/(x-3y)
=x(x+3y)/(x-3y)(x+3y)
=(x²+3xy)/(9x²-y²)